At the end, when the second to last guy hits a line drive, you see the crowd. There is a fan turned around wearing a Derek Jeter jersey. Since there are no current Yankees that exist in the movie, that jersey cannot exist. To top it off, the 2 and the Jeter above it are backwards.

I don't know how much of a slip-up this really is, at least in the context you mentioned it.
New York Yankees jerseys don't have names above the number. Check it out sometime. Now, whether you can buy them with names, I don't know. I think this is a slip-up in that context...the other, I'm not sure. He's not the first player to wear number 2.